COMPACT(1)              COMMAND REFERENCE              COMPACT(1)



NAME
     compact - compress files

SYNOPSIS
     compact [ filename ... ]

DESCRIPTION
     Compact compresses the named files using an adaptive Huffman
     code. If no filenames are given, the standard input is
     compacted to the standard output.  Compact operates as an
     on-line algorithm. Each time a byte is read, it is encoded
     immediately according to the current prefix code.  This code
     is an optimal Huffman code for the set of frequencies seen
     so far.  It is unnecessary to prepend a decoding tree to the
     compressed file since the encoder and the decoder start in
     the same state and stay synchronized. Furthermore, compact
     and uncompact can operate as filters. In particular,


           ... | compact | uncompact | ...

     operates as a (very slow) no-op.

     When an argument filename is given, it is compacted and the
     resulting file is placed in filename.C; filename is
     unlinked. The first two bytes of the compacted file code the
     fact that the file is compacted. This code is used to
     prohibit recompaction.

     The amount of compression to be expected depends on the type
     of file being compressed. Typical values of compression are:
     Text (38%), Pascal Source (43%), C Source (36%) and Binary
     (19%).  These values are the percentages of file bytes
     reduced.

EXAMPLES
     The following example compacts the file prog.c:



          compact prog.c


     The resulting compacted data is in the file prog.c.C.  The
     file prog.c is removed.

FILES
     *.C                      Compacted file created by compact.

RETURN VALUE
     [NO_ERRS]      Command completed without error.




Printed 10/17/86                                                1

COMPACT(1)              COMMAND REFERENCE              COMPACT(1)



     [NP_WARN]      An error warranting a warning message
                    occurred. Execution continues.

     [NP_ERR]       An error occurred that was not a system
                    error.  Execution terminated.

     [P_WARN]       A system error occurred. Execution continues.
                    See intro(2) for more information on system
                    errors.

SEE ALSO
     ccat(1), uncompact(1).











































Printed 10/17/86                                                2

%%index%%
na:72,60;
sy:132,146;
de:278,1575;
ex:1853,266;
fi:2119,106;
rv:2225,133;2502,392;
se:2894,149;
%%index%%000000000129